numpy_eigen 3rdParty dependency

[Andrew Melim]

@ptf 's numpy_eigen library is required to use numpy arrays with the gtsam python wrapper. I have a basic setup with numpy_eigen in a separate bitbucket project. This project modifies the build system to utilize a pure cmake system as opposed to the orginal which required rosbuild

However, this is not ideal and is not portable if we wish to ship the python wrapper with gtsam source code.

We need to determine the following

• Should we include numpy_eigen in the gtsam project proper

• If so, where should the project be included. I'm not sure if gtsam/3rdParty is the correct place since those are c++ deps

• Are there any licensing issues we should be aware of @ptf?

Tagging @dellaert

[Frank Dellaert]

Not an issue with cython wrapper